Lubricating oil pump



. INVENTOR.

March 11, 1958 i J. LlPlNsKl V LUBRICATING OIL PUMP Filed Aug. 9, 1954 rates LUBRICATING OIL PUMP Application August 9, 1954, Serial No. 448,478 Claims priority, application Austria February 16, 1954 6 Claims. (Cl. 184-27) The invention relates to a lubricating oil pump in which the oil ows at a rate metered by a metering pump through a drip gap or nozzle and an overhead receiving pan to the working space of a feed piston. In most lubricating oil pumps of this type, several pump units, comprising at least a metering piston with adjustable stroke and a feed piston, are accommodated in a common pump casing from which the oil ows to the metering piston. The metering and feeding functions are allocated to different elernents to keep the relatively high feed pressure from the metering flow rate of the lubricant is controlled with higher accuracy. In that case, however, the precision of the pump is impaired considerably by air enclosed in the working space of the feed piston. This applies especially to pumps or pump units with horizontal feed pistons and a lateral or upwardly directed discharge valve connection. The precision is greatly reduced by the possibility of air being fed from the working space through the discharge Valve to the point of lubrication. The air can mix with the oil fed and the removal of air may be irnpossible, particularly in the case of viscous lubricating oil. Besides, the air which has entered the working space of the feed piston may obstruct the inflow of the oil metered by the metering pump into the working space of the feed piston.

It is an object of the invention to eliminate these disadvantages in lubricating oil pumps comprising a metering pump or metering piston and a feed piston supplied by said metering pump or piston through a drip gap or nozzle and a receiving pan. Essentially the invention resides in the provision of separate paths for the oil inflow to and for the air exhaust from the working space of the feed piston. According to the invention the oil inflow path is connected at a low level to the working space of the feed piston and the air exhaust path is connected to the uppermost point of said space to avoid mixing between oil and air to a considerable extent. That separation may be assisted by forming the oil inow line to the Working space of the feed piston in the form of a a Siphon to maintain a permanent liquid seal between the working space of the feed piston and the receiving pan. Both connection openings can be controlled by the feed piston moving past them. Suitably the arrangement is such as to close both connection openings at the same time. The air exhaust path may discharge into the receiving pan, which is not sealed against atmosphere in any case. This precludes the entrance of foreign matter into the working space of the feed piston by way of the air exhaust path andan escape of oil into the open along the air exhaust path is avoided.

En a preferred embodiment of the invention the working space of the feed piston communicates by way of a sealing trap with the discharge valve leading to the feed line. The metering piston or metering pump will feed different quantities of lubricant during one working cycle of the feed piston, depending on the rate setting. Howpump or metering piston so that the ate-t ever, even the largest amount of lubricant for which theY pump has been set must be accommodated by the working space of the feed piston. Though the working space of the feed piston is Vented according to the invention so as to avoid a mixing of oil and air to a considerable extent, a certain amount of air will mostly be present in the working space of the feed piston. The Siphon connected in front of the discharge valve will prevent that air enclosed in the working space of the feed piston from being fed through the discharge valve to the point of lubrication. Suitably the volume of the space enclosed between the feed piston at the end of the feed stroke and the lowermost point of the siphon is at least equal the maximum handling volume of the metering piston during a working cycle of the feed piston, to prevent air from lbeing fed through the siphon to the discharge valve and the lubricating line even at the lowest rate setting or when the metering pump or metering piston is not handling lubricant at all.

In the drawing an illustrative example of the invention is shown diagrammatically. The drawing is a vertical sectional view of the pump serted therein.

In the oil-filled pump casing 1 the pump shaft 2 is casing and a pump unit inrotatably mounted, whose eccentric portion 3 is embraced by a follower 4, at which the cylinder 5 of the metering piston 6 and the feed piston 7 are located. As the follower 4 moves to the left an inlet bore d of the metering cylinder 5 passes an inlet bore 9 of the guide cylinder 10 for the metering cylinder 5, to admit oil from the oil reservoir 11 of the pump casing l into the working space 12 of the metering piston 6. During that movement to the left a collar 13 of the metering piston 6 engages a stop edge 14 of the guide cylinder 10 to pull the metering piston 6 from the working space 12 of the metering cylinder 5. The discharge stroke of the metering piston is effected by its engagement with an adjustable stop screw 15, whose setting determines the amount of lubricating oil handled by metering piston 6. The oil is fed out of the working space 12 through an outlet bore 16 of metering cylinder 5, which bore exposes an outlet bore 17 of the guide cylinder 10 during the discharge stroke of the metering piston 6. From there the lubricating oil is fed through bores 18, 19 of the pump casing 1 and in the form of freely falling drops into the receiving pan 2l from a drip gap or nozzle 20.

From the receiving pan 21 the lubricating oil flows through a bore 22 to an inlet bore 23 of the feed piston cylinder 24; the bore 23 is controlled by the feed piston 7. The feed piston cylinder 24 has a recess 25 forming an annular space which -connects the inlet bore 23 with the duct 22. Whereas the lubricating oil flows from bore 22 through that annular space 25 to inlet bore 23, the air which has entered the working space 26 of the feed piston 7 is discharged through a bore 27 provided at the uppermost point of that working space. Bore 27 also opens into duct 22 but its discharge opening is above the oil level in that space so that the air exhaust is separated entirely from the oil supply. Depending on the rate at which the lubricating oil flows into the working space 26 of the feed piston 7 the air flows from that working space through bore 27 into the receiving pan 21 without mixing with the lubricating oil.

From the `working space 26 the lubricating oil is fed through a spring-loaded discharge valve 2S into the lubricant line 29. Between the working space 26 and the discharge valve 28 a disc 30 is interposed, which has an opening 31. Since that opening lies below the lowermost point of working space 26, a sealing trap is provided which maintains a liquid seal between working space 26 and discharge valve 28. The space 32 in front of opening 31 at the lowermost point of the sealing trap Patented liv/lar. 1l, 1958* isat leastequal in size to the-maximum oil volume that can be-handled by metering piston 6- during a--working cycle of feed piston 7, so that the sealing trap cannot become empty in any case and the oil seal between the workingspace 261andthe discharge valve-ZS-is permanently maintained. What I claim is:

1; In'. a'- lubricating oilpump, a metering` pump, a horizontally disposedfeed piston having a cylinder and a working space'tlierein,` a receiving pan and a drip nozzle,A the' oil fed by the saidV metering pump being delivered'through the said-drip nozzle to the said receiving pan, said cylinder having an o-il inlet opening and ank air escape opening therein, and a passage for the oil leading! froml the saidl receiving pan to the said inlet opening, the said escape opening beingin communication with said-receiving pan..

2.'- In a lubricatingfoilpumpV asclaimed' in claim thersaid oilvinlet opening being disposed atrthe lower partA of said cylinder andi the-said air escape openingV an' annular spacesurrounding the: said cylinder inthe region of the'saidloil-inlet opening'andformirrg'part'of the said oil passage to theL said oil` inlet opening; the'V said air escape opening inthe-said cylinder beingdisl posed at a point above the level of the oil flowing to the said annular space.v

5. In a lubricating oil pump, a metering pump, a horizontally disposed feed piston having a cylinder and a working space therein, a receiving pan and a drip nozzle, the oil fed by the said metering pump being delivered through said drip nozzle to the said receiving pan, the said cylinder having an oil inlet opening in communication with the said receiving pan, an outlet for' the lubricant' fed by.- the feed piston, said working space'la'v'in'gaV discharge end'to the said outlet, a space in connection with said discharge end, a second space and a communicatingopeningdisposed at avlower level than the lowermost generatrix of4 said cylinder and connecting the two spaces, said two spaces and the com municating opening. forming a sealingy trap, and a dischage valve between the sealing trap and said outlet.

6, In a lubricating oil pump as claimed in claim 5, the volume enclosed betweenthe'v feed) pistonat the end off its. feed` stroke andthelsaid' communicating opening being y at least-equal, tothe maximumA delivery volume of the` saidmetering pumpduring one working cycle of the saidlfeed l piston;

References' Cited in the le of this patent UNITED STATES PATENTS 1,032,487y Manzel July 16, 1912 1,571,915 Prier Feb. 2, 1926 1,949,272 Fries v Feb. 27, 1934 2,449,596 Ericson Sept. 21, 1948 2,499,784 Schmidt Mar. 7, 1950 2,603,158 Nemetz' July 15, 1952 

